On October 23rd, 2014, we updated our
By continuing to use LinkedIn’s SlideShare service, you agree to the revised terms, so please take a few minutes to review them.
Two major categories for the application of
radiation for cancer treatment are externalbeam therapy and brachytherapy. For
external-beam treatment, the patient lies
underneath a machine that emits radiation or
generates a beam of x-rays. This tech-nique is
also called teletherapy, or long- distance
treatment. Most cancer patients are treated in
this fashion. However, some pa-tients may also
be treated with brachyther-apy.
• from the Greek word
βραχυς brachys, meaning "shortdistance“.
• Also known as internal
radiotherapy, sealed source
radiotherapy, curietherapy or
•A type of radiation therapy
used to treat
cancer, involving the
placement of a radioactive
inside the body.
• Unlike EBRT which delivers an
external radiation source through
healthy tissue (‘from the
outside, in’), brachytherapy delivers
the radioactive dose directly within or
adjacent to the tumor (‘from the
Brachytherapy works ‘from
the inside, out’
External beam radiotherapy
works ‘from the outside, in’
• The theory behind brachytherapy is to
deliver low-intensity radiation over an
extended period to a relatively small
volume of tissue.
• The low intensity isotopes are placed
directly into a tissue or cavity depositing
radiation only a short distance, covering
the tumor area but sparing surrounding
• This technique allows a higher total
dose of radiation to be delivered to
the tumor than is achievable with
external beam radiation alone.
A brief timeline
Henri Becquerel, a French
physicist, accidentally discovered
radioactivity. He noticed that
Uranium caused a black spot to
appear on a photographic plate that
had not been exposed to sunlight.
This discovery raised interest into
the effects of radiation, which
would later lead to the first use of
First use of
Pierre Curie (a French physicist who
studied the effects of radioactivity)
suggested to Henri-Alexander Danlos
(a French doctor) that radioactivity
could be use to treat cancer. Danlos
tested the idea and found that
radiation caused cancer tumors to
shrink. Early techniques of
brachytherapy were pioneered at the
Curie Institute in Paris by Danlos and
at St. Luke’s and Memorial Hospital in
New York by a surgeon called Robert
P i e r re Cu r i e
In the years after the first use of
brachytherapy, a number of
doctors pioneered the
application of it to treat different
types of cancer. These included
Margaret Cleaves in the field of
cervical cancer, Hugh Hampton
Young and Benjamin Barringer in
the field of prostate cancer and
Geoffrey Keynes in the field of
One of the early challenges of
brachytherapy is ensuring the
healthcare professionals delivering
treatment were not exposed to
radiation on a daily basis. By 1970’s,
special machine known as
‘afterloaders’ were made available.
Afterloaders contain the radiation
sources used for high dose rate
brachytherapy. Staff can remotely
control the ‘afterloader’ from a
separate observation room to deliver
the radiation from the machine into the
A modern afterloader machine
In the 1990s, various imaging
technologies, such as
ultrasound, magnetic resonance
imaging (MRI) and computed
tomography (CT) scans become more
widely available. These technologies
help doctors plan the brachytherapy
procedures. They can also be used
during the brachytherapy procedure to
ensure the radiation is precisely
delivered to exactly the right place.
Ultrasound image of the prostate
At the turn of the new century,
advanced computerized brachytherapy
planning systems were introduced.
These enable healthcare professionals
to accurately plan the delivery of the
radiation using a virtual 3D
representation of the patient. Doctors
can then precisely target the radiation
to the cancerous tumor and avoid
damage to the healthy surrounding
Creation of a 3D ‘virtual’ patient
Robotic delivery of
Prostate seed therapy
The first robotic device to
brachytherapy for prostate
cancer (seed therapy) was
innovations such as this
have helped to make
brachytherapy even more
effective and safe.
Robotic delivery of seed therapy
• Brachytherapy can be used in combination with other
therapies such as surgery, EBRT or
chemotherapy, particularly when the tumor is too large or is
not easily accessible.
• Brachytherapy has been most widely applied in the treatment
Brachytherapy can also be used
to treat tumors in several other
Body sites in which brachytherapy
can be used to treat cancer
Brachytherapy can be characterized
according to three main factors:
• Source placement
• Treatment duration &
• Dose rate
ACCORDING TO SOURCE
• Interstitial - the sources are placed directly in the
target tissue of the affected site, such as the prostate or
• Contact - involves placement of the radiation
source in a space next to the target tissue.
Intracavitary – A body cavity such as cervix, uterus or vagina.
Intraluminal – A body lumen such as the trachea or esophagus.
Surface (Mould) – externally such as the skin.
Intravascular – Blood vessels.
ACCORDING TO TREATMENT DURATION
• Temporary- Dose is delivered over a short period of
time and the sources are removed after the prescribed dose
has been reached. The specific treatment duration will
depend on many different factors, including the required
rate of dose delivery and the type, size and location of the
also known as seed implantation,
involves placing small LDR radioactive seeds or
pellets (about the size of a grain of rice) in the
tumour or treatment site and leaving them there
permanently to gradually decay.
ACCORDING TO DOSE RATE
• Low-dose rate(LDR)- Emit radiation at a rate of 0.4–
2 Gy/hour. Commonly used for cancers of the oral
cavity, oropharynx, sarcomas and prostate cancer
• Medium-dose rate (MDR)- characterized by a medium
rate of dose delivery, ranging between 2-12 Gy/hour.
• High-dose rate (HDR)-when the rate of dose delivery
exceeds 12 Gy/h.
• Pulsed-dose rate (PDR) - involves short pulses of
radiation, typically once an hour, to simulate the overall
rate and effectiveness of LDR treatment.
Source placed next
to the tumor
Source place within Breast, Prostate
for a specific
temporary for a
wide variety of
• In brachytherapy, the radiation dose is applied to
tumor by sealed sources. The sources are
implanted to the tumor tissue itself or in its close
• They are enclosed in a protective capsule or wire
which allows the ionizing radiation to escape
to treat and kill surrounding tissue, but
prevents the charge of radioisotope from
moving or dissolving in body fluids.
• Sources can be tubes, needles, wires, pellets or
• Brachytherapy sources are usually
encapsulated; the capsule serves several
• Containing the radioactivity;
• Providing source rigidity;
• Absorbing any alpha and, for photon emitting
sources, beta radiation produced through the
• The choice of an appropriate photon emitting
radionuclide for a specific brachytherapy treatment
depends on several relevant physical and dosimetric
characteristics, the most important of which are the:
Photon energies and photon beam penetration
into tissue and the shielding materials;
Half-value layer (HVL) in shielding materials such
Inverse square fall-off of dose with distance from
the source (this is the dominant dosimetric
effect, because of the very short treatment
distances used in brachytherapy).
1.17, 1.33 MeV
0.38 MeV (mean)
27.4, 31.4 and
21 keV (mean)
Commonly used radiation sources (radionuclides) for brachytherapy
• Symbol: (137Cs)
• Half-Life: 30.17 years
• Energy: 0.662 MeV
• most widely used source for the
treatment of gynecological
• distributed within an insoluble
glass or ceramic matrix
• encapsulated in stainless-steel
sheaths with wall thicknesses of
0.5 to 1.0 mm, active lengths of
13.5 to 15 mm, diameters of 2.6
to 3.1 mm, and total lengths of
about 20 mm.
• Symbol: (60Co)
• Half-Life: 5.26 years
• Energy: 1.17-1.33 MeV
• In the form of wire which is encapsulated in
a sheath of platinum, iridium or stainless
• available as pellets with a typical
activity of 18.5 GBq (0.5 Ci) per pellet.
• Symbol: (192Ir)
• Half-Life: 30.17 years
• Energy: 73.8 days
• available in the form of seeds, 0.5 mm in
diameter and 3 mm long, for LDR BT
• Also used in the form of a wire (0.3-mm
or 0.6-mm outer diameter) consisting
of an iridium-platinum radioactive core
encased in a 0.1-mm sheath of platinum.
• Symbol: (125I)
• Half-Life: 59.6 days
• Energy: 35.5 keV
• Used for permanent implants
• Only available as seeds. They are usually
inserted into the tumour volume using
special delivery ‘guns’.
Source storage and handling
Radioactive sources must be under the control
of an appropriate person at all times…
Source stores must:
provide protection against environmental conditions
be only for radioactive
provide sufficient shielding
be resistant to fire
ACCOUNTABILITY OF SOURCES
Source accountancy records should contain:
radionuclide and activity of sources
location and description of sources
The records should
be updated regularly,
and the location of the
Secure (lock and key)
TRANSFERRING SOURCES FROM AND
INTO A SAFE
Use of tweezers
Short transport ways
HANDLING OF SOURCES
no eating/drinking in room
use long forceps
Let someone know if you work with
• A computerized medical device that
drives a small radioactive source
through catheters to predetermined
dwell positions for a specific time in a
patient's body during brachytherapy.
• A device used to hold a radioactive
source in place during brachytherapy.
• Applicators are non-radioactive and
are typically needles or plastic
catheters. The specific type of
applicator used will depend on the
type of cancer being treated and the
characteristics of the target tumor.
Typical stages of a brachytherapy procedure.
• In order to accurately plan the brachytherapy
procedure, a thorough clinical examination is
performed to understand the characteristics of
• A range of imaging modalities can be used to
visualize the shape and size of the tumor and its
relation to surrounding tissues and organs.
• Data from many of these sources can be used to
create a 3D visualization of the tumor and the
• This initial planning helps to ensure
that ‘cold spots’ (too little
irradiation) and ‘hot spots’ (too
much irradiation) are avoided during
treatment, as these can respectively
result in treatment failure and sideeffects.
INSERTION AND IMAGING OF THE
• Before radioactive sources can be delivered to the
tumor site, the applicators have to be inserted and
correctly positioned in line with the initial
• Imaging techniques, such as x-ray, fluoroscopy
and ultrasound are typically used to help guide
the placement of the applicators to their correct
positions and to further refine the treatment plan.
• CAT scans and MRI can also be used.
• Once the applicators are inserted, they
are held in place against the skin using
sutures or adhesive tape to prevent them
from moving. Once the applicators are
confirmed as being in the correct
position, further imaging can be
performed to guide detailed treatment
CREATION OF A VIRTUAL
• The treatment planning software enables
multiple 2D images of the treatment site to be
translated into a 3D ‘virtual patient’, within which
the position of the applicators can be defined.
• The spatial relationships between the
applicators, the treatment site and the
surrounding healthy tissues within this ‘virtual
patient’ are a copy of the relationships in the
• The sources used in Brachytherapy can be delivered
manually, but are more commonly delivered through a
technique known as ‘afterloading’.
• Manual delivery of brachytherapy is limited to a few LDR
applications, due to risk of radiation exposure to clinical
• In contrast, afterloading involves the accurate positioning
of non-radioactive applicators in the treatment site,
which are subsequently loaded with the radiation sources.
In manual afterloading, the source is delivered into the
applicator by the operator
• Once the applicators are correctly positioned in the
patient, they are connected to an ‘afterloader’ machine
(containing the radioactive sources) through a series of
connecting guide tubes.
• The treatment plan is sent to the afterloader, which then
controls the delivery of the sources along the guide tubes into
the pre-specified positions within the applicator.
• This process is only engaged once staff are removed from the
• The sources remain in place for a pre-specified length of
time, again following the treatment plan, following which they
are returned along the tubes to the afterloader.
• literally "one who stands
• Tubuloalveolar exocrine gland
of the male reproductive system
in most mammals.
• A walnut-sized gland located
between the bladder and the
• A healthy human prostate
is classically said to be
slightly larger than a
• The mean weight of the
normal prostate in adult
males is about 11 grams,
usually ranging between 7
and 16 grams.
• It surrounds the urethra
just below the urinary
bladder and can be felt
during a rectal exam.
The function of the prostate is
to secrete a slightly alkaline
fluid, milky or white in
constitutes 50–75% of the
volume of the semen along
with spermatozoa and seminal
• Brachytherapy takes 30 minutes or more, depending on
the type of therapy you have. Before the procedure, you
will be given medicine so that you do not feel pain. You
• A sedative to make you drowsy and numbing medicine
on your perineum. This is the area between the anus
• Anesthesia. With spinal anesthesia, you will be drowsy
but awake, and numb below the waist. With general
anesthesia, you will be asleep and pain-free.
After you receive anesthesia:
• The doctor places an ultrasound probe into your
rectum to view the area. The probe is like a camera
connected to a video monitor in the
room. A catheter (tube) may be placed in your
bladder to drain urine.
• The doctor uses ultrasound or a CT scan to plan
and then place the seeds that deliver radiation into
your prostate. The seeds are placed with needles or
special applicators through your perineum.
• Placing the seeds may hurt a little (if you are
Types of brachytherapy
• Low-dose radiation brachytherapy is the most
common type of treatment. The seeds stay inside
your prostate and put out a small amount of
radiation for several months. You go about your
normal routine with the seeds in place.
• High-dose radiation brachytherapy lasts about
30 minutes. Your doctor inserts the radioactive
material into the prostate. The doctor may use a
computerized robot to do this. The radioactive
material is removed right away after treatment.
WHY THE PROCEDURE IS PERFORMED?
• Brachytherapy is often used for men
with a small prostate cancer that is
found early and is slow-growing.
Brachytherapy has fewer
complications and side effects than
standard radiation therapy. You will
also need fewer visits with the doctor.
BEFORE THE PROCEDURE
Tell your doctor or nurse what medicines you are taking. These
include medicines, supplements, or herbs you bought without a
Before this procedure:
• You may need to have ultrasounds, x-rays, or CT scans to prepare
for the procedure.
• Several days before the procedure, you may be told to stop
taking medicines that make it hard for your blood to clot. These
medicines include aspirin, ibuprofen (Advil), clopidogrel
(Plavix), and warfarin (Coumadin).
• Ask your doctor which medicines you should still take on the day
of the surgery.
• If you smoke, try to stop. Your doctor or nurse can help.
ON THE DAY OF THE
• You will likely be asked not to drink or eat
anything for several hours before the
• Take the medicines your doctor told you to
take with a small sip of water.
• Your doctor or nurse will tell you when to
arrive at the hospital. Be sure to arrive on
AFTER THE PROCEDURE
• You may be sleepy and have mild pain and tenderness after
• After an outpatient procedure, you can go home as soon as
the anesthesia wears off. In rare cases, you will need to
spend 1 - 2 days in the hospital. If you stay in the hospital,
your visitors will need to follow special radiation safety
• If you have a permanent implant, your doctor may tell you
to limit the amount of time you spend around children and
women who are pregnant. After a few weeks to months,
the radiation is gone and will not cause any harm. Because
of this, there is no need to take out the seeds.